Responsible: LEHNA – R. Angulo Jaramillo
Participants: LEHNA & DEEP with the support of University of Palermo, LEM & IFSTTAR
Objectives
Development of a large ring (~1m diam.) infiltrometer for injecting water and high-tech nano-tracers (engineered nanoparticles) & design of a method for depicting water bulbs and nano-tracer pathways in the soils, using non-intrusive geophysical methods (i.e. Ground Penetrating Radar, GPR). Field tests in an instrumented pilot in Django Reinhardt infiltration basin monitored by OTHU (the Field Observatory for urban water management – www.othu.org) [71, 87, 88].
Description of work
Large ring water infiltration – nano-tracer injection experiments will be based on the infiltration of water and nano-tracers through a large ring (about 1m in diameter) while maintaining a constant water depth in the ring (analogy made with Beerkan experiments, [47]). During water infiltration, water content at the surface around the ring will be monitored using water content TDR probes. In addition, the soil surface will be photographed to map wetting front, which is representative of the extension of the infiltration bulb at the surface. Water will be colored using dyes to increase the contrast between wet and unwetted soil as suggested by [17]. Ground Penetrating Radar will be used to track the pathways of the nano-tracers and water, the nano-tracers being designed to behave as contrasting agent for GPR. Data includes the water cumulative infiltration at surface, dynamics of the extension of water corolla around the ring, and GPR signal. In addition, interstitial water in the soil will be sampled below the ring, using specific devices to validate the information derived from GPR signal for flow and the nano-tracer pathways. For this purpose, infiltration experiments will be carried out near the experimental well developed in the pilot infiltration basin (Django Reinhardt) [34]. The access well (2 m in diameter and in depth) is equipped with probes for the measurement of water pressure head, water content and for the sampling of interstitial water at different depths. This set of experiment will allow us to test the engineered nano-tracer in a strongly heterogeneous deposit, known to be prone to preferential flow. Another set of infiltration experiments will be performed using stormwater with bacteria and nano-pollutants (anthropic nanoparticles). Their fate in the deposit will be characterized and compared to that of the nano-tracers to validate the representativeness of the engineered nano-tracers under real conditions. The techniques developed to inject and track anthropic nanoparticles and bacteria are described in task 3.
Role of participants
LEHNA will design the water infiltration & nano-tracer injection experiments and develop the use of geophysics methods (i.e. GPR) for the monitoring of infiltration bulbs and nano-tracer pathways. LEHNA will benefit from the support of University of Palermo for the design of infiltration experiment, ILM for the development, use and detection of the nano-tracers, and LEM and IFSTTAR for the detection and tracking of indigenous bacteria and anthropic nanoparticles.
Risks and contingency plan
The LEHNA team has great experience in water infiltration experiments and related modelling. The infiltration of water in a new large infiltrometer should not bring significant risk of failure. Conversely, the utilization of new chemical (nano-tracers) on the field is more challenging. Great care will be taken to avoid any environmental and sanitary risk associated to the use of the engineered nano-tracers. Another significant challenge lies in the use of geophysics (GPR) to detect the nano-tracers below the infiltrometer (see risk management section and task 2). Several alternatives and spare tracers (solutes and salts) will be considered.
Deliverables / milestones
- D1.1 INFILTRON-exp toolbox for assessing infiltration & filtration functions.
- D1.2 The consortium will assess the potential for the deposition of a patent for INFILTRON-exp.
- M1.1 Design and settlement of a field pilot for infiltration tests
- M1.2 Design of a large infiltrometer for water infiltration and nano-tracers injection
- M1.3 Field tests with designed nano-tracers for Ground Penetrating Radar (GPR)
- M1.4 Field Tests with designed nano-tracers for mimicking bacteria & emerging pollutants